Instrument case construction



March 1969 c. J. GOODWIN 3,430,498

INSTRUMENT CASE CONS TRUCTION Filed April 26, 1967 United States Patent 4 Claims ABSTRACT OF THE DISCLOSURE A housing for instruments in which the parts simply snap-fit together. The mechanism enclosed within the housing is mounted on a dial plate which is slidably mounted within a pair of guide members projecting from the walls of the housing.

This invention relates generally to housings for instruments of the thermometer, barometer, etc., type and more particularly concerns an instrument case suitable for a variety of such instruments.

The primary aim of the invention is to provide an instrument case which can be economically formed and easily assembled. A collateral object is to provide such a case which is well suited for containing any of a variety of instruments and which is easily adapted for a particular mounting.

In more detail, it is an object of the invention to provide a case of the above character which, when formed of resilient plastic parts, simply snaps together without the need for tools or special fixtures.

Another object is to provide a case which gives a long scale for the instrument although the case is relatively compact.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:

FIGURE 1 is a perspective of the instrument having a case embodying the present invention;

FIG. 2 is an enlarged transverse section, partially exploded, of the instrument shown in FIG. 1;

FIG. 3 is a rear elevation of the body shell of the instrument case shown in FIGS. 1 and 2;

FIG. 4 is a section taken approximately along the line 44 in FIG. 3;

FIG. 5 is a bottom view of a portion of the instrument case taken along the line 5--5 in FIG. 2; and

FIG. 6 is a fragmentary section taken approximately along the line 66 in FIG. 2.

While the invention will be described in connection with a preferred embodiment, it will be understood that I do not intend to limit the invention to that embodiment. On the contrary, I intend to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention.

Turning first to FIG. 1, there is shown an instrument 10, in this case a thermometer, mounted in a case 11 embodying the invention. The case 11 includes a box-like shell 12 having an open side 13 and a window opening 14. Preferably, the open side 13 is at the rear of the case 11 and the window opening is at the upper front of the instrument 10.

A transparent lens 15, preferably formed of resilient plastic, is mounted in the window opening 14. In the illustrated form, the lens 15 is substantially semicylindrical having a curved front portion 16 and a semicircular top portion 17. The curved portion 16 nests in a shelf 18 formed as a portion of the shell 12, and the top portion 17 includes a tab 19 which fits within a recess 20 in the inside of the top portion of the shell 12. In the preice ferred arrangement, the front portion of the lens 16 includes a second tab 21 that fits within a recess 22 when the lens is seated in the shelf 18. Thus, to mount the lens 15 in place, the curved portion 16 is seated in the shelf 18 with the tab 21 fitted in the recess 22, and the top portion 17 is then deflected slightly to permit the tab 19 to be snap-locked into the recess 20.

In carrying out the invention, opposite sides of the shell 12 are formed with a set of opposed guides 24 and 25 defined by a pair of projecting ridges, and a mounting plate 26 is provided which is proportioned to fit within the shell 12 and which has resilient fingers 27 that engage the guides 24, 25. In a preferred form, the plate 26 is formed of resilient plastic and the fingers 27 are integrally formed in pairs on each side of the plate. In place, the fingers 27 are slightly tensioned to hold the plate 26 resiliently in position. Also, the plate is formed with an integral semicylindrical dial 28 that is configured to fit just behind the curved portion 16 of the lens. The dial 28 bears the indicia shown in FIG. 1.

The mounting plate 26 supports a thermometer mechanism 30 on its underside, and a shaft 31 of the mechanism 30 extends through the plate 26 and supports a pointer 32 having its ends folded down to move over the dial 28. As familiar to those skilled in this art, a householdtype thermometer, as is the mechanism 30, is a relatively simple device including a temperature-responsive element 33 in spiral form having its outer end held by a calibrating lever 34 and its inner end secured to the shaft 31 holding the pointer 32. The lever 34 pivots on a collar 35 through which the shaft 31 passes and which secures the mechanism 30 to the plate 26. Preferably, the plate 26 includes integral posts 37 intended to facilitate the mounting of other mechanisms such as those suitable for indicating barometric pressure, relative humidity, etc. Any instrument can be conveniently mounted, tested and adjusted on the plate 26 with its integral dial 28 before the entire assembly of plate and mechanism is slipped into the shell 12.

Pursuant to the invention, a wall 40' is provided proportioned to close the shell opening 13, and the wall is formed with resilient tines 41 which extend within the shell 12 and mate with recesses 42 formed in the top and bottom walls of the shell. In the preferred arrangement, the wall 40 and its tines 41 are formed integrally of resilient plastic so that the wall can be slightly distorted to snap-lock the tines 41 into the recesses 42, thus closing the open side 13 of the shell .12. The wall 40 is also formed with an opening 43 providing access to the calibrating lever 34, and an opening 44 which serves as an eyelet for Wall mounting the instrument 10 on a hook or stud. To insure that wall mounting does not affect accuracy of the instrument 10, the shell 12 is preferably formed with long slots 46 in the front of the shell to provide a grill-like opening in the case which is not blocked whether the instrument is wall mounted or table supported.

As a feature of the invention, the plate 26 is formed with a set of resilient fingers 45 which bear on the wall 40 when the latter is snap-locked into position, and the fingers 27 on the plate 26 engage the lens 15 with the lens serving as a stop for the plate 26 when the plate is slid ihto the guides 24, 25. Thus, when the case 11 is in assembled relation, the plate 26 is sandwiched between the wall 40 and the lens 15, and the resilient fingers 45 create a resilient force acting against both the wall and the lens to hold these parts against play and looseness.

In the illustrated instrument, a reference or memory pointer 47 is mounted on a shaft 48 which carries an outside knob 49. By rotating the knob 49, the pointer 47 can be used to mark readings of the pointer 32 for later convenient comparisons.

It can now be seen that the instrument case described above can be very economically formed of molded plastic, and that assembly is simply a matter of snapping the parts into engagement. Any type of instrument desired can be conveniently mounted on the mounting plate 26 and the instrument can be tested and adjusted before assembly into the case. The curved dial 28 provides a particularly long scale in a compact instrument case. The resiliency and snap action of the mating parts permits ready disassembly of the instrument case should that be required for servicing.

I claim as my invention:

1. An instrument case comprising, in combination, an integral box-like shell having an open side and a window opening, a transparent lens in said opening, a set of opposed guides formed within said shell on opposite sides thereof, a mounting plate proportioned to fit within said shell and having integral resilient fingers slidably engaged within said guides and tensioned to resiliently hold the plate in position, a wall proportioned to close said open side and having resilient tines, said shell having recesses receiving said tines in snap-locking engagement with the wall closing said open side, and said plate having another resilient finger bearing on said wall to resiliently hold the wall and the plate against looseness.

2. The combination of claim 1 in which said mounting plate is formed with a dial that is displayed beneath said lens, and the combination includes a mechanism mounted on said plate and having a pointer positioned for movement over said dial and beneath said lens.

3. The combination of claim 2 in which said lens is substantially semicylindrical and protrudes from said shell, and said dial is configured to fit within said lens.

4. The combination of claim 1 in which said lens is formed of resilient material and is snap-locked onto said shell, and said plate bears against said lens so that the plate is resiliently sandwiched between the lens and said wall.

References Cited UNITED STATES PATENTS 962,469 6/1910 Ross 22082 X 2,130,863 9/1938 Stickney et al. 324-156 2,612,132 9/1952 Triplett 73-431 X 2,866,940 12/1958 Lamb 22082 X 3,101,155 8/1963 Lehr et al. 220-4 3,166,941 1/1965 Waite et al 7343l 3,298,351 1/1967 KoZa 73-431 X LOUIS R. PRINCE, Primary Examiner.

D. M. YASICH, Assistant Examiner.

U.S. Cl. X.R. 

